I have come across many people over the years rant or rave about wearing plus lenses as a therapy for myopia. Plenty of opinions from both extremes, and everything in between. Are they the best way to reverse myopia? Do they cause additional vision problems? Are they ok for limited purposes?
It’s hard to answer those questions definitely, but this is an attempt to explain how I look at it.
What Are Plus Lenses?
First you have to understand what myopia (nearsightedness) is optically. There is a convex lens inside the eye that causes the light rays to converge, or focus, onto the retina. The light rays being bent in any manner like this is called refraction. In a myopic eye, the light rays are focused in front of the retina, ie: the rays are converged too much, so they cross in front of the retina and then separate again and hit the retina in a disordered array, creating blur.
Eyeglass lenses prescribed for myopia (nearsightedness) are concave, meaning they’re thicker on the edges than in the middle. This causes light rays passing through it to diverge. This prescription for myopia is written down as a negative or “minus” number, such as -3.00 diopters. So the light rays are diverged through the eyeglass lens, then they pass through the myopic eye’s convex lens, the result being that the light rays come to a focus on the retina. The -3 diopter lens compensated for the over-focusing of the eye.
For hyperopia (farsightedness) or for old-age presbyopia, it’s the opposite. The amount of under focus is written as a positive number, because a convex eyeglass lens is used to add additional focusing power.
So when a person with myopia wears a convex lens meant to correct farsightedness, the result is even more blur, as the light comes to a focus even farther in front of the retina.
How Plus Lens Therapy Works
Here is the theory behind it.
Basically the idea is the eye adapts to whatever focusing environment it is predominantly exposed to. So for someone who does not wear glasses, regardless of whether they “need” them or not, focusing up close for near work will cause the eye to become more myopic. Focusing a little farther away will cause a slower myopic shift, and focusing for the distance will not increase myopia. Plus lenses change the focusing level required, such that the eye does not need to focus much (or at all) for nearwork, but the distance will become (more) blurry to a myopic or normal sighted person. So by wearing plus lenses, the effect is such that focusing near will have little or no effect, while focusing for distance will cause a hyperopic shift, or away from myopia, or in other words lessening the degree of myopia. If the use of plus lenses is continued, myopia will be entirely eliminated, the eye will focus perfectly, and if it is continued further, the eye will become hyperopic.
So that is the explanation for plus lenses in a nutshell. It isn’t a system of eye exercises like many programs you’ll find on the internet, but a way of using certain glasses prescriptions.
My Take on Plus Lens Therapy
I’ve had the experience of looking up from a long session of reading to find that the distance has gotten blurry (or blurrier), which is one thing that plus lens therapy advocates will point to. Indeed, that was one of the first things I noticed when I started looking into vision improvement. But even then I noticed that there were exceptions, and I had found ways to temporarily improve my vision such that I could see that my quality of vision was not simply a result of the focusing level my eyes had been doing. Moreover, other students spent many hours studying as well and did not become myopic the way the theory said they should, and they weren’t farsighted either. Over time I started to see more consistently how my mental state and how I thought about what I was looking at had much more to do with my quality of vision than any time spent doing any near- or distance-looking task.
I believe myopia, like some other vision problems, is a psycho-physiological disorder. Myopia is caused not by too much near work, but by how dexterously the visual system operates while doing not only near work but far work. Vision is an incredibly complex task, and when the balance is thrown off or some parts are suppressed by stress, tiredness or misuse, myopia and other problems result, depending on the predispositions of the person.
It isn’t what the eye is exposed to, but how the eye, and the brain, are used or misused by the conscious individual.
You bend over to pick up a box the wrong way, you hurt your back. You don’t chew your food, you choke. We have the freedom to do things badly with our bodies and the responsibility to do things right. Vision is no different. There is a right way to use the eyes, and there are consequences to the wrong ways. Myopia is one such consequence.
So to me, plus lenses are an unnecessary interference. If you want to restore the natural function of your visual system, introducing a factor that creates such an extreme artificial environment to confuse the hell out of it is not a good idea.
Plus lenses may have some short-term effects as the visual system reacts, but with such an approach your visual system will become dependent on the plus lenses not only to improve but to avoid getting worse. Advocates admit that constant use of plus lenses, over a period of years, is necessary to cause the necessary changes by 1/2 diopter per year. That’s incredibly slow.
Aspirin works to relieve your headache, but what else is the aspirin doing to you? Pain medication messes with the signals. And plus lenses likewise mess with the signals in your brain regarding how the eye needs to focus. It’s presumptuous to interfere with those, whether by chemical or mechanical means, and not expect side effects or undesired long term consequences. I’m just speaking generally here. That’s my philosophy of unnecessary intervention into systems that are made to run themselves and adjust as needed.
Plus lenses also interfere with your peripheral vision the same as minus lenses do. Peripheral vision is an important component that a well-functioning visual system uses to calibrate itself. Glasses teach you to suppress the perception of everything that isn’t directly in front of you.
The lack of plus lenses did not cause myopia, and plus lenses are not needed to solve the problem and are not an appropriate solution.
I understand if you’re confused and frustrated and if plus lenses seem like a simple solution when you just don’t understand the Bates method. If there were a simple solution that anyone could learn in a few minutes, I would be all for it. Believe me, I dislike unnecessary complexity. But plus lenses are not the simple solution you’re looking for. The real solution is already available to you, and I have written about it endlessly in this blog.
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I founded iblindness.org in 2002 as I began reading books on the Bates Method and became interested in vision improvement. I believe that everyone who is motivated can identify the roots of their vision problems and apply behavioral changes to solve them.